Technical Field
The present invention relates to a liposome for treating cancer by including doxorubicin, a polyunsaturated fatty acid, and beta glucan in combination.
Description of the Related Art
The “background” description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description which may not otherwise qualify as prior art at the time of filing, are neither expressly or impliedly admitted as prior art against the present invention.
Doxorubicin (DOX) has been found to have a broad spectrum of application in cancer, which includes numerous solid tumors such as breast cancer, sarcomas and bladder cancers. See Weinstein D M, Mihm M J, Bauer J A. “Cardiac peroxynitrite formation and left ventricular dysfunction following doxorubicin treatment in mice,” J Pharmacol Exp Ther 2000; 294: 396-401, incorporated herein by reference in its entirety. Despite its common use, the clinical utility of DOX is compromised by dose-limiting cardiotoxicity due to its effects on mitochondria. The heart contains a large amount of energy producing mitochondria to function as a pump which requires a great amount of energy that circulates blood throughout the body. See Angsutararux P, Luanpitpong S, Issaragrisil S. “Chemotherapy-Induced Cardiotoxicity: Overview of the Roles of Oxidative Stress,” Oxid Med Cell Longev 2015; 2015: 795602, incorporated herein by reference in its entirety. A mitochondrion is the site of most reactive oxygen species (ROS) which are produced as a result of electrons escaping from electron transport chain and captured by oxygen, rendering it as a main source of superoxide production. See Andreyev A Y, Kushnareva Y E, Murphy A N et al. “Mitochondrial ROS Metabolism: 10 Years Later,” Biochemistry (Most) 2015; 80: 517-31, incorporated herein by reference in its entirety. However, DOX can drive these ROS production to much higher levels. See Varin R, Mulder P, Richard V et al. “Exercise improves flow-mediated vasodilatation of skeletal muscle arteries in rats with chronic heart failure. Role of nitric oxide, prostanoids, and oxidant stress,” Circulation 1999; 99: 2951-7. Recent research suggests that nitric oxide (NO) may play diverse roles in cardiac function and disease. High level of NO production is associated with multiple forms of cardiac disease, including dilated cardiomyopathy and congestive heart failure. See Fadillioglu E, Yilmaz H R, Erdogan H et al. The activities of tissue xanthine oxidase and adenosine deaminase and the levels of hydroxyproline and nitric oxide in rat hearts subjected to doxorubicin: protective effect of erdosteine. Toxicology 2003; 191: 153-8, incorporated herein by reference in its entirety. A mechanism to reduce cardiotoxicity from DOX is of interest to the medical community.
Glucans are important secondary metabolites isolated from plants and micro-organisms. Glucans are generally described as a polysaccharide of D-glucose monomers, linked by glycosidic bonds. They exhibit prophylactic and therapeutic properties, and can function as biological response modifiers when administered to mammals. As such, glucans have shown beneficial effects in the treatment of infectious and autoimmune diseases, and in clinical management of cancer.
Glucans target various cell types in the immune system, and more particularly macrophages. Previous research has shown that glucans display protective properties against experimentally induced infections in mammalian model systems. Specifically, glucans exert their function on macrophages, monocytes, lymphocytes, and other immune cells in the mammalian system that plays a significant role in elicitation of the immune response.
For example, administration of glucans has been shown to significantly enhance the immune system in animals to a wide variety of experimentally induced bacterial, viral, fungal and parasitic infections. Glucans also show strong anti-tumor activity. Glucan carries out its biological function by binding to specific receptor molecules located on the surface of macrophages. In in vitro studies, exposure of these cells to beta-glucans stimulates the immune system. One representative glucan with such immune-enhancing characteristics is branched beta (1,3)-glucan.
Beta-glucans are naturally occurring polymers of saccharides (polysaccharides) and are constituents of the cell wall of certain pathogenic bacteria, algae, fungi, and cereals (e.g. oats, barley, rye, wheat). The healing and immunostimulating properties of mushrooms have been known for thousands of years in the Eastern countries. These mushrooms contain biologically active polysaccharides that mostly belong to group of beta-glucans. Beta-glucans can increase host immune defense by enhancing macrophages and natural killer cell function. The induction of cellular responses by beta-glucans is likely to involve their specific interaction with several cell surface receptors, such as complement receptor 3 (CR3; CD11b/CD18), lactosylceramide, selected scavenger receptors, and dectin-1 (betaGR). As an immunostimulating agent, which acts through the activation of macrophages and NK cell cytotoxicity, beta-glucan can inhibit tumor growth in promotion stage also. The interaction between glucan and its receptor produce further stimulatory effects such as enhanced phagocytosis, increased cell size, enhanced cell proliferation, enhanced adherence and chemotactic activity and production of a wide range of cytokines and leukotrienes.
Cytokines are critical to a myriad of fundamental homeostatic and pathophysiological processes such as fever, wound healing, inflammation, tissue repair and fibrosis. They play important roles in regulating cell function such as proliferation, migration, and matrix synthesis. It is the balance or the net effect of the complex interplay between these mediators, which appears to play a major role in regulating the initiation, progression and resolution of wounds. Wound healing involves a complex process including induction of acute inflammation by the initial injury, followed by parenchymal and mesenchymal cell proliferation, migration, and activation with production and deposition of extracellular matrix.
A study reported that β-glucan has immunomodulation effect on innate and adaptive immunity. See Thompson I J, Oyston P C, Williamson D E. “Potential of the beta-glucans to enhance innate resistance to biological agents,” Expert Rev Anti Infect Ther 2010; 8: 339-52, incorporated herein by reference in its entirety. β-glucan react on immune receptors such as dectin-1 to trigger cell response including monocytes, macrophages, neutrophils, natural killer cells and dendritic cells. See Fang J, Wang Y, Lv X et al. “Structure of a beta-glucan from Grifola frondosa and its antitumor effect by activating Dectin-1/Syk/NF-kappaB signaling,” Glycoconj J 2012; 29: 365-77; Lee S Y, Lee Y G, Byeon S E et al. “Mitogen activated protein kinases are prime signalling enzymes in nitric oxide production induced by soluble beta-glucan from Sparassis crispa,” Arch Pharm Res 2010; 33: 1753-60, each incorporated herein by reference in its entirety. As a consequence of activation of dectin-1 signaling pathway, cytokines including interleukin IL-12, IL-6, IL-10 and tumor necrosis factors are released. These cytokines might play a major role in the cancer therapy uses for β-glucan. See Chan G C, Chan W K, Sze D M. “The effects of beta-glucan on human immune and cancer cells,” J Hematol Oncol 2009; 2: 25, incorporated herein by reference in its entirety, which describes Maitake D-Fraction extracted from Grifola frondosa (Maitake mushroom) was found to decrease the size of the lung, liver and breast tumors in >60% of patients when it was combined with chemotherapy in a 2 arms control study comparing with chemotherapy alone (page 8, right column, lines 1-5). Previous studies showed that β-glucan increased cytotoxicity and synergized with a specific anti-tumor monoclonal antibody in killing tumor cells. See Cheung N K, Modak S, Vickers A et al. “Orally administered beta-glucans enhance anti-tumor effects of monoclonal antibodies,” Cancer Immunol Immunother 2002; 51: 557-64, incorporated herein by reference in its entirety. Another study reported the anticancer activity of β-glucan on human dermal cells through induction of caspase-12 expression. See Choromanska A, Kulbacka J, Rembialkowska N et al. Anticancer properties of low molecular weight oat beta-glucan—An in vitro study. Int J Biol Macromol 2015; 80: 23-8, incorporated herein by reference in its entirety.
As cancer chemoprevention research has advanced, interest toward investigation of natural products such as omega-3. Several studies demonstrated the beneficial effect of omega-3 as antioxidant, anti-inflammatory and anti-apoptotic agent. Uygur et al. examined administration of omega-3 along with doxorubicin and found that omega-3 protect against DOX acute cardiotoxicity in vivo due to the antioxidant and anti-apoptotic properties. See Zararsiz I, Kus I, Akpolat N et al. “Protective effects of omega-3 essential fatty acids against formaldehyde-induced neuronal damage in prefrontal cortex of rats,” Cell Biochem Funct 2006; 24: 237-44; Zararsiz I, Sonmez M F, Yilmaz H R et al. “Effects of omega-3 essential fatty acids against formaldehyde-induced nephropathy in rats,” Toxicol Ind Health 2006; 22: 223-9; Ellulu M S, Khaza'ai H, Patimah I et al. “Effect of long chain omega-3 polyunsaturated fatty acids on inflammation and metabolic markers in hypertensive and/or diabetic obese adults: a randomized controlled trial,” Food Nutr Res 2016; 60: 29268; Uygur R, Aktas C, Tulubas F et al. “Cardioprotective effects of fish omega-3 fatty acids on doxorubicin-induced cardiotoxicity in rats,” Hum Exp Toxicol 2014; 33: 435-45, each incorporated herein by reference in its entirety.
In addition to natural products, several carrier systems have been developed to increase efficacy of cancer treatment and decrease toxicity such as liposomes. Liposomes consist of one or more lipid bilayers surrounding an aqueous core. They are a relatively safe delivery system because they are biocompatible and biodegradable. See Alhariri M, Azghani A, Omri A. “Liposomal antibiotics for the treatment of infectious diseases,” Expert Opin Drug Deliv 2013; 10: 1515-32, included herein by reference in its entirety.
In view of the forgoing, one objective of the present invention is to provide a liposomal formulation that has beta-glucan, doxorubicin, and omega-3, -6, and/or -9 lipids, for an improved therapeutic liposome for cancer treatment.